public void ApplyTo(Sidedef s)
        {
            s.ClearFlags();
            foreach (var group in Flags)
            {
                s.SetFlag(group.Key, group.Value);
            }

            s.OffsetX         = OffsetX;
            s.OffsetY         = OffsetY;
            s.RepeatX         = RepeatX;
            s.RepeatY         = RepeatY;
            s.TileIndex       = TileIndex;
            s.MaskedTileIndex = MaskedTileIndex;
            s.Shade           = Shade;
            s.PaletteIndex    = PaletteIndex;

            s.HiTag = HiTag;
            s.LoTag = LoTag;
            s.Extra = Extra;
        }